(MCT) -- Mazda plans to show off the next generation MX-5 Miata roadster this September at simultaneous events in Japan, Spain and the U.S.

The small Japanese automaker reinvented the two-seat roadster class when it introduced the rear-wheel-drive convertible 25 years ago. Since then, Mazda has sold more than 900,000 internationally, making it the best-selling two-seat roadster in automotive history.

This will be the fourth-generation MX-5. It was called the Miata when the car first launched in the U.S., but Mazda uses that only as a nickname now. Officially the car is the MX-5, to fit with the automaker's global alphanumeric naming convention.

Since its introduction, Mazda has used the MX-5 to communicate the automaker's sporty design philosophy, said Karl Brauer, an analyst with auto information company Kelley Blue Book.

"It is the heart and soul of the entire brand," Brauer said. "The rest of the Mazda line is supposed to have the MX-5's sporty, fun-to-drive demeanor."

The redesigned roadster will get what Mazda calls SkyActiv technology, a package of improvements already used in the automaker's other models. This design philosophy shaves weight from the vehicle and wrings efficiency out of a standard gasoline engine and drivetrain without employing hybrid technology or continuously variable transmissions.

The new MX-5 chassis, for example, will weigh about 220 pounds less than the current version, Mazda said. This approach allows Mazda to save money in research and development and stay competitive with its much bigger Japanese rivals, including Honda, Nissan and Toyota.

Mazda didn't disclose many details about the new car or provide a photo.

Although the engine is in the front, Mazda is pushing the weight of the powertrain closer to the middle by locating heavier components at the rear of the engine.

The engine will be behind the front axle, though automakers typically put the engine above it. Mazda's design places the sports car's center of gravity lower than that of any previous generation. Like earlier models, the new MX-5 will have a 50/50 weight distribution to ensure balanced handling.

The automaker didn't disclose a price for the new MX-5. The current model starts around $24,000. Mazda made minor changes to the vehicle in 2013 but it was last redesigned in 2006, making it the oldest vehicle among Mazda's U.S. offerings.

Sales of the sports car have slowed. Mazda has sold about 2,700 through the first half of this year, a 15 percent decline from the same period in the prior year.

Still, the Miata has long been a favorite of U.S. auto enthusiasts. The two-seat open cockpit design is reminiscent of the British Triumphs and MG roadsters of the 1960s and '70s, and Italian sports cars such as the Alfa Romeo Spider. Other automakers such as Honda, Pontiac and Saturn have offered rival models over the years, but none matched Mazda's success. "While it was inspired by the British roadsters, Mazda now owns the concept," Brauer said.

Just days after Mazda's planned Sept. 3 reveal of the new MX-5, it will take the car to the Mazda Raceway Laguna Seca near Monterey, Calif., for a gathering of Miata enthusiasts. Owners of the sports car will be able to race their cars on the track and attend talks by Mazda designers. Already, more than 1,500 people are registered for the event.